Abstract: The DC system of power plants provides stable power supply for control, protection, and emergency equipment. Grounding faults may cause serious consequences such as equipment misoperation and unit shutdown. This paper focuses on the environmental characteristics of power plants, analyzes the types of faults such as single point grounding and multi-point grounding in DC systems, explores practical detection methods such as portable inspection instruments and insulation monitoring devices, and proposes measures such as graded troubleshooting and equipment modification to provide reference for grounding fault prevention and control for power plant operation and maintenance.